In recent years, continuous positive airway pressure (CPAP) therapy has become a common prescription for individuals suffering from sleep apnea and/or other breathing ailments. Such therapy may involve placement of a nose or face mask on the subject during sleeping, while positive pressure air is continuously delivered to the subject through the mask. In some cases, such CPAP treatment may materially lessen the incidents and/or severity of sleep apnea, thereby allowing the subject to sleep or rest with less disturbances.
A common problem encountered with prior CPAP nose mask assemblies is the tendency to leak positive pressure air at one or more locations, such as between connections of mask assembly components and/or between the mask assembly and the subject's face, e.g., where the cheek regions and nose intersect. Leaks between the mask and the subject's face are particularly common due to the wide ranges of shapes and sizes of the heads and faces of different subjects. Leaks within a mask assembly or between the mask assembly and the subject's face may be undesirable for various reasons. For example, leaks may reduce the positive pressure of the air being delivered to the subject. As another example, leaks between the mask and the subject's face may tends to dry the subject's eyes, creating uncomfortable wearing and operating conditions. As another example, leaks may produce noises, which may be undesirable to the subject and/or the subject's bed partner. One typical way to reduce leaks is to provide a tighter compressive fit of the mask against the nose and face of the wearer. However, too tight of a fit may cause discomfort to the subject.